echoVanguard wrote:and he has no way of knowing if he was the first to open the box (and thus the sender or receiver of the catbit).
Not quite what Frank's saying. Frank has claimed (and is correct) that you can circumvent this particular problem by
scheduling the measurements. I.e., scientist 1 and 2 are light-years away, and scientist 2 is scheduled to measure his particle one minute later than scientist 1. Ergo, as soon as scientist 2 opens his box he learns about an event that happened a light year away even though it happened only a minute ago.
But this sort of thing happens all the time, and it's not sufficient to show FTL transfer of information. Here's a classical example:
1) You cut a coin down the middle, producing a heads-side and a tails-side. You randomly put each in an envelope.
2) You hand these envelopes to two individuals, and tell them travel a few light years apart. You schedule person A to open their envelop one minute before person B.
3) Person A opens their envelope, and gets some result.
4) Person B opens their envelope, and gets the opposite result. They now also know person A's result, even though they are light-years away and the event happened a minute ago.
C) Was this FTL transfer of information? No. You're deducing a third piece of information from two others: if you get result X (subluminal information, personally observed), and their result is the complement of your's (subluminal information, known from the experiment description), ergo their result was the opposite of X (deduced, not transmitted).
The reason the quantum mechanical equivalent throws everyone for a loop is because the values in the coin experiment are decided at the beginning of the experiment, and the values in the quantum experiment are decided the first time someone measures. It fucks with human intuition, and it does require the propagation of some effect (but not necessarily information) FTL. But the lesson to take away holds whether it's classical coins or quantum particles:
"spooky learning at a distance" is necessary but not sufficient to show FTL communication. We need something
more to show a transfer of information occurred faster-than-light.
(But even with scheduling, the problem I've been trying to describe holds. No action you can take effects the probability of results experienced at the other end, so you can't send a bit. Grek did the explicit math for the 1-dimensional case where Bob and Alice are both measuring the same axis. The math is a lot more complicated as you add dimensions and the ability to measure different axes, but the results don't change.)
EDIT: P.S...
magical spin rays + scheduling -> FTL communication. Scientist 1 can force either +X or -X to transmit bits, and then inbetween those intervals scientist 2 measures his particle to receive them.
persistent entangling + scheduling -> FTL communication. Scientist 1 measures his particle until he gets the desired result (the bigger the gap in the schedule, the more time he has to get the desired result; it works out to be equivalent to forcing with a transmission error rate that approaches 0 as time approaches infinity).